The field of the invention is synthetic resins with fat, fatty oil, fatty oil acid or salt thereof. The present invention is particularly concerned with electrophoretically deposited coatings which dry at room temperature. These coatings can also be cured in an accelerated manner at temperatures of up to 85.degree. C in order to shorten the drying time.
The state of the prior art of electrophoretic deposition of coatings from aqueous suspension may be ascertained by reference to the Kirk-Othmer "Encyclopedia of Chemical Technology", 1st Ed., Vol. 5(1950), under the section "Electrophoretic Deposition", pages 606-610 and Vol. 8, 2nd Ed. (1965), under the section "Electrophoretic Deposition", pages 23 - 26. The preparation, designation and use of the cyclized rubber used in the present invention is disclosed in Kirk-Othmer, 2nd Ed., Vol. 17(1968), pages 651-655, U.S. Pat. No. 2,661,340 of Van Veersen and British Patent 634,879 of Gordon.
Processes for the electrophoretic formation of coatings on metallic workpieces by dipping the object, connected as the anode, into an electric dip coating bath are conventional. In order to cure these coatings, they had to be baked heretofore, without exception, at temperatures of more than 120.degree. C over a longer period of time. By the use of the conventional electrocoating processes, only baked enamel coatings could be produced heretofore. Thus, Swiss Patent 419,770 describes a process for the electrophoretic production of a synthetic resin coating wherein baking enamels are employed containing, as the binders, acrylate resins, alkyd resins, or maleate oils by themselves or in combination with urea resins or melamine resins. These coatings are baked for at least one-half hour at at least 120.degree. or 130.degree. C.
U.S. Pat. No. 3,230,162 of Gilchrist, dated Jan. 18, 1966, likewise discloses an anodic electrocoating process wherein baked enamel coatings are produced with the use of neutralized polycarboxylic acid resins.
In British Patents 1,161,819 and 1,168,269, the electrophoretic deposition of acrylate polymers from their neutralized aqueous solutions is set forth. In this case, however, it is necessary to bake the coatings for at least 20 minutes at at least 170.degree. C in order to obtain cured films.
At temperatures of below 100.degree. C, the prior art deposited coatings remain tacky and do not harden. However, this means that coatings are obtained without any useful technological and corrosion-protective properties. For the curing of baked enamel coatings, high temperatures and thus also high amounts of energy are required. The use of baked enamel coatings is essentially limited to the coating of metals. For the electrocoating of heat-sensitive materials, such as wooden materials, rubber articles, or synthetic resin and plastic articles, it is generally impossible to employ baked enamel coatings. In this case, air-drying coatings must be used. In the extreme case, it is possible to operate at slightly increased temperatures, up to a maximum of 85.degree. C. Otherwise, the articles to be coated are damaged. The accelerated drying of airdrying coatings at an elevated temperature up to 85.degree. C is sometimes necessary in order to obtain certain mechanical and corrosion-protective results. In order to increase the spectrum of applications of electrocoating, it has been desirable to discover air-drying electrocoatings.